PCB winding transformer and coil board thereof

Abstract

The present disclosure discloses a PCB winding transformer and a coil board thereof. The PCB winding transformer comprises a coil board and a magnetic core. The coil board includes a primary coil and a secondary coil. The primary coil and the secondary coil are wound around a magnetic core column of the magnetic core. At least two via holes which correspond to the primary coil and the secondary coil respectively are disposed in the coil board. In the primary coil and the secondary coil, the via hole corresponding to the coil with less turns is disposed between an inner side of the coil with more turns and the magnetic core column.

What is claimed is: 
     
       1. A PCB winding transformer, comprising a magnetic core and a coil board,
 wherein the coil board comprises a primary coil and a secondary coil winding around a magnetic core column of the magnetic core and being arranged in a multilayer structure, with the secondary coil comprising two turns, one turn of the secondary coil located in a first layer and the other turn of the secondary coil located in a last layer, and the primary coil comprising more turns than the secondary coil being located in intermediate layers, 
 wherein at least one via hole for connecting respective layers of the secondary coil are disposed in the coil board, and 
 wherein in a plane in which the primary coil is located, the at least one via hole for connecting respective layers of the secondary coil is disposed between an inner side of the primary coil and the magnetic core column, 
 the PCB winding transformer further comprises a switching device disposed on and at least partly overlapped with the secondary coil. 
 
     
     
       2. The PCB winding transformer according to  claim 1 , wherein the switching device is a secondary synchronous rectifier disposed on the secondary coil. 
     
     
       3. The PCB winding transformer according to  claim 1 , wherein the switching device is a secondary rectifier diode disposed on the secondary coil. 
     
     
       4. The PCB winding transformer according to  claim 1 , wherein the switching device is a primary power switch disposed on the primary coil. 
     
     
       5. The PCB winding transformer according to  claim 1 , wherein the PCB winding transformer is used in a flyback converter. 
     
     
       6. A coil board, comprising a primary coil, a secondary coil and a through hole corresponding to a magnetic core column of a magnetic core,
 wherein the primary coil and the secondary coil are wound around the magnetic core column and being arranged in a multilayer structure, with the secondary coil comprising two turns, one turn of the secondary coil located in a first layer and the other turn of the secondary coil located in a last layer, and the primary coil comprising more turns than the secondary coil being located in intermediate layers, 
 wherein at least one via hole for connecting respective layers of the secondary coil are disposed in the coil board, 
 wherein in a plane in which the primary coil is located, the at least one via hole for connecting respective layers of the secondary coil is disposed between an inner side of the primary coil and the through hole, and 
 wherein a switching device is disposed on and at least partly overlapped with the secondary coil. 
 
     
     
       7. The coil board according to  claim 6 , wherein the switching device is a secondary synchronous rectifier disposed on the secondary coil. 
     
     
       8. The coil board according to  claim 6 , wherein the switching device is a secondary rectifier diode disposed on the secondary coil. 
     
     
       9. The coil board according to  claim 6 , wherein the switching device is a primary power switch disposed on the primary coil.